This invention relates to a method of measuring strain applied to one or more optical fibres. A particular application of the invention concerns the measurement of strain produced by pressure applied to a system, thus providing a method of measuring pressure.
A transducer for measuring strain or pressure that provides an optical output has the advantage that it is not disturbed by electromagnetic interference at other than optical frequencies. This is particularly desirable for making measurements in electromagnetically noisy environments such as at various points inside a jet engine. Moreover, for this sort of purpose, an optical signal is preferred to a fluidics signal, since the latter is vulnerable to the vibrations and accelerations present in such environments, and is less readily able to withstand the extreme temperature range over which operation may be required.